PdTe₂ Transition‐Metal Dichalcogenide: Chemical Reactivity, Thermal Stability, and Device Implementation

Abstract

Palladium ditelluride (PdTe 2 ) is a novel transition-metal dichalcogenide exhibiting type-II Dirac fermions and topological superconductivity. To assess its potential in technology, its chemical and thermal stability is investigated by means of surfacescience techniques, complemented by density functional theory, with successive implementation in electronics, specifically in a millimeter-wave receiver. While water adsorption is energetically unfavorable at room temperature, due to a differential Gibbs free energy of ≈+12 kJ mol −1 , the presence of Te vacancies makes PdTe 2 surfaces unstable toward surface oxidation with the emergence of a TeO 2 skin, whose thickness remains sub-nanometric even after one year in air. Correspondingly, the measured photocurrent of PdTe 2 -based optoelectronic devices shows negligible changes (below 4%) in a timescale of one month, thus excluding the need of encapsulation in the nanofabrication process. Remarkably, the responsivity of a PdTe 2 -based millimeter-wave receiver is 13 and 21 times higher than similar devices based on black phosphorus and graphene in the same operational conditions, respectively. It is also discovered that pristine PdTe 2 is thermally stable in a temperature range extending even above 500 K, thus paving the way toward PdTe 2 -based high-temperature electronics. Finally, it is shown that the TeO 2 skin, formed upon air exposure, can be removed by thermal reduction via heating in vacuum.Chemical and thermal stability represent crucial bottlenecks in the prospect of technological exploitation of materials "beyond graphene." [7] Definitely, chemical instability is usually associated with the chemical reactivity of the surface [8] and to presence of intrinsic [9] or extrinsic [8]

Magnetic Topological Semimetal Phase with Electronic Correlation Enhancement in SmSbTe

“…Topological materials are a promising platform for a wide range of next‐generation technologies. [ 1–16 ] In topological Dirac or Weyl semimetals, symmetry‐protected Dirac or Weyl nodes host relativistic fermions with low‐energy excitations that can be described by Dirac or Weyl equations, respectively. [ 4,5 ] In addition, topological nodal‐line semimetals exhibiting linear band crossings along a 1D loop have also been discovered.…”

Chemical Synthesis and Integration of Highly Conductive PdTe2 with Low‐Dimensional Semiconductors for p‐Type Transistors with Low Contact Barriers

“…The atomically resolved STEM images of the transferred PdTe 2 sample at multiple locations revealed the periodic atom arrangement with the typical 1T structure, composed of one central Pd and six Te atoms located at octahedral points (Figure 2c and Figures S8d,S9, and S10, Supporting Information). [ 22 ] In addition, the X‐ray diffraction (XRD) patterns of the as‐synthesized PdTe 2 films exhibited prominent diffraction peaks (Figure S11, Supporting Information). The inverse pole figure (IPF) mapping obtained by electron backscattered diffraction (EBSD) demonstrated the (001) dominant orientation and micrometer‐sized crystal grains in PdTe 2 films (Figure S12, Supporting Information).…”

Regulating thermochemical redox temperature via oxygen defect engineering for protection of solar molten salt receivers

“…In this work, the DFT calculations were conducted with a CASTEP module in Materials Studio 8.0. The generalized gradient approximation (GGA) with Perdew-Burke-Erzernhof (PBE) type was used for electron exchange-correlation (Muhich et al, 2015;D'Olimpio et al, 2019). As shown in Figure S8, the 23231 supercells with 20 atoms were created and optimized to estimate the substitution effect of Mn element semiquantitatively.…”